Synthetic crystalline aluminosilicate for the catalytic conversion of hydrocarbons in petrochemical processes

ABSTRACT

Synthetic crystalline aluminosilicate of the pentasil type and method for using the same as catalysts or catalyst components in petrochemical processes for the catalytic conversion of hydrocarbons and their derivatives into useful organic compounds and intermediates.

This is a division of application Ser. No. 07/725,809, filed Jul. 8,1991, now U.S. Pat. No. 5,407,654, which is a continuation-in-part ofU.S. patent application Ser. No. 549,185, filed Jul. 6, 1990, nowabandoned, the disclosure of which is incorporated herein by referencein its entirety.

The present invention relates to synthetic crystalline aluminosilicatesand their use as catalysts or catalyst components in petrochemicalprocesses for the conversion of hydrocarbons and their derivatives intovaluable organic intermediates. The chemical composition of thealuminosilicates of the invention is described in terms of molar ratiosin the following manner:

    (0-3) M.sub.2 O:Al.sub.2 O.sub.3 :(15-40) SiO.sub.2 :(0-40) H.sub.2 O

wherein M represents an alkali metal cation, proton, or an ammoniumcompound.

BACKGROUND OF THE INVENTION

The development and application of molecular sieve catalysts withshape-selective properties has, without doubt, provided an impetus inrecent decades to the development of crude oil processing andpetrochemistry. This is so particularly since the discovery ofsilicon-rich zeolites of medium pore size of the pentasil type.

Pentasil aluminosilicate zeolites are important catalysts in thepetroleum and chemical industries and have been applied in processeswhich (1) lower or eliminate lead and benzene in motor gasoline; (2)replace concentrated liquid or carrier-supported mineral acid catalysts,i.e. sulfuric acid, hydrofluoric acid and phosphoric acid, in aromaticalkylation and olefin hydration processes; and (3) limit the content ofaromatics and sulfur in diesel fuels.

Structurally, pentasil zeolites are characterized by an intracrystallinesystem of mutually crossing channels with a diameter of about 5.5angstroms. The crossing regions have a very weakly pronounced cagecharacter and are frequently the site of the reaction occurrence. Inaddition to the acid strength of the acidic centers and theirconcentration, pore shape and size have an important influence on theactivity and selectivity of the conversion of materials and materialmixtures.

The size of the pore canals permits the entry and exit of linear andonce branched aliphatic molecules and of aromatic molecules with asingle benzene ring with up to 10 carbon atoms. Molecules of this classare converted chemically within the pore structure and released asproduct by diffusion processes. The intracrystalline diffusion ratevaries considerably between members of this class due to the differencesin molecular size and form. In cases where the activated state of themolecule requires more space than can be satisfied by the crossingregions of the pentasil zeolites, such reactions do not proceed orproceed only with very low probability. This selective property inzeolites is known as shape-selectivity.

The behavior of zeolite catalysts is largely determined by finedifferences within the aluminosilicate structure. For example, it isknown that the aluminum distribution over the cross section of pentasilzeolite crystals synthesized using organic template compounds isdifferent from that of pentasil zeolite crystals obtained from strictlyinorganic synthesis batches (see, for example, A. Tissler et al. Stud.Surf. Sci. Catal. Vol. 46, pages 399-408 (1988)). For the former case,aluminum accumulation in the periphery of the crystals is observed; forthe latter, the aluminum over the cross section of the crystalspredominates. Structural information of the zeolite provided by X-raycrystal diffraction is therefore not sufficient to characterize thecatalytic utility of such materials and needs to be supplemented by moresubtle methods such as solid state high resolution nuclear magneticresonance (NMR) spectroscopy. For a review on the applications of solidstate NMR in structural characterization of zeolites, see, Engelhardt,G. et al. "High-Resolution Solid State NMR of Silicates and Zeolites,"Wiley; Chichester, England, 1987.

Pentasil zeolites in their protonated form catalyze a variety ofreaction types which include: (1) dehydration/hydration (ethers andalkenes from alcohols, alcohols from alkenes), (2) carbon-carbon bondlinking reactions (oligomerization of alkenes, condensations ofoxygen-containing compounds and alkylation of aromatic compounds andisoparaffins); (3) carbon-carbon bond splitting reactions (crackingprocesses of paraffins and alkenes); (4) aromatization (synthesis ofaromatic compounds from paraffins and alkenes); and (5) isomerizations(backbone and double bond isomerizations).

Methods for the synthesis of aluminosilicates are described extensivelyin the technical and patent literature (see, for example, Jacobs, P. A.et al. (1987) Stud. Surf. Sci. Cat., Vol. 33, pages 113-146). Thereported methods for the synthesis of aluminosilicates, however, sufferfrom a variety of serious disadvantages which preclude their use forindustrial scale, non-polluting production. Examples of suchdisadvantages include: (1) the use of materials which are toxic andinflammable; (2) formation of undesirable secondary phases, e.g. quartz,in the zeolite product; (3) prolonged reaction times; (4) incompletereactions; and (5) the use of high temperatures to remove organiccontaminants, e.g. structure-directing compounds as quaternary ammoniumsalts, present in the zeolite lattice which damages the latticestructures leading to a reduction in the catalytic properties. Inaddition, formation of toxic effluents under conventional synthetichydrothermal conditions necessitates costly pollution control equipment.

For example, U.S. Pat. No. 3,702,886 discloses the synthesis ofsilicon-rich zeolites of the pentasil family. The disclosed methods forzeolite synthesis requires the presence of organic, structure-directingcompounds or templates in the reaction mixture. Tetralkylammoniumcompounds, e.g. tetrapropylammonium bromide, are generally used for thispurpose.

U.S. Pat. No. 4,257,885 discloses a process for preparing zeolites whichomits the use of organic templates. The synthetic processes describedtherein lead to the desired product under prolonged (several days)reaction times which may not reach completion.

Accordingly, there is a substantial need in the field for improvedmethods for preparing crystalline aluminosilicates which avoid at one ormore of the deficiencies mentioned above. Furthermore, there is an acuteneed in the art for synthetic, crystalline aluminosilicates whichdisplay enhanced catalytic properties, long-term stability, and higherselectivity over conventional aluminosilicates in petrochemicalprocesses.

SUMMARY OF THE INVENTION

The present invention relates to synthetic crystalline aluminosilicatesand methods for using the same as catalysts or components inheterogeneous catalysts for petrochemical processes for the conversionof hydrocarbons and their derivatives into valuable organicintermediates.

The synthetic crystalline aluminosilicates are produced by hydrothermalcrystallization from an inorganic aqueous alkaline reaction mixturehaving a composition of SiO₂ /Al₂ O₃ at a molar ratio between about 15and about 40; OH⁻ /SiO₂ at a molar ratio between about 0.1 to about 0.2;and a H₂ O/SiO₂ at a molar ratio between about 20 and about 60.

The aluminosilicates of the present invention display enhanced catalyticproperties, long-term stability, and higher selectivity overconventional aluminosilicates. In addition, the inventivealuminosilicates are synthesized by a strictly inorganic method whichexcludes formation of undesirable secondary phases, prolonged reactiontime, and produces higher product yield over conventional methods. Inaddition, the inventive aluminosilicates have a low coking tendencywhich allows long operating periods between catalyst regeneration.

The inventive aluminosilicate can be used as catalysts and catalystcomponents for converting hydrocarbons and its derivatives into valuableintermediates in the petrochemical industries. For example, thealuminosilicates can be used in processes for (1) removing n-paraffinsor once branched paraffins from hydrocarbon fractions; (2) processing ofmixtures of C8 aromatic compounds; (3) alkylating aromatic compoundswith low molecular weight alkenes and alcohols; (4) crackinghigher-boiling hydrocarbon fractions on agitated catalysts; (5)isomerizing low molecular weight n-paraffins to iso-paraffins; (6)generating aromatic compounds from low molecular weight hydrocarbons;(7) generating liquid hydrocarbons from low molecular weight alkanes andalkenes and (8) converting alcohols to hydrocarbons, low molecularweight alkenes and aromatic compounds.

OBJECTS OF THE INVENTION

Accordingly, it is an object of the invention to provide a synthetic,crystalline aluminosilicate of the pentasil type having a largelyhomogeneous distribution of aluminum over the crystalline cross-section,hence a surface molar ratio of SiO₂ :Al₂ O₃ which is equal to or greaterthan the interior molar ratio of SiO₂ :Al₂ O₃ in the crystal. Thealuminosilicate of the present invention exhibits enhanced catalyticproperties, selectivity, and stability over known aluminosilicatesprepared by conventional methods employing organic templates.

It is another object of the invention to provide a method of using theinventive aluminosilicate as a catalyst or a component of a heterogenouscatalyst for the catalytic conversion of hydrocarbons and theirderivatives in petrochemical processes.

It is yet another object of the invention to provide a practical methodfor preparing synthetic crystalline aluminosilicates which does notrequire the use of organic templates and prolonged reaction times, doesnot produce undesirable secondary phases and produces a higher productyield over conventional methods.

These and other objects of the invention will be apparent in light ofthe detailed description below.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ²⁹ Si solid state MAS NMR spectrum of the aluminosilicatetype A zeolite prepared in accordance with Example 1.

FIG. 2 is a ²⁹ Si solid state MAS NMR spectrum of aluminosilicate type Bzeolite prepared in accordance with Example 2.

FIG. 3 is a ²⁹ Si solid state MAS NMR spectrum of aluminosilicate type Czeolite prepared in accordance with Example 3.

FIG. 4 is an electron beam micro-probe analysis illustrating thecross-sectional aluminum distribution of aluminumsilicate type A zeoliteprepared in accordance with Example 1.

FIG. 5 is an electron beam micro-probe analysis illustrating thecross-sectional aluminum distribution of aluminumsilicate type B zeoliteprepared in accordance with Example 2.

FIG. 6 is an electron beam micro-probe analysis illustrating thecross-sectional aluminum distribution of a conventional aluminosilicatetype C zeolite prepared in accordance with Example 3. This figuredemonstrates the accumulation of aluminum at the periphery of thezeolite crystals.

DETAILED DESCRIPTION OF THE INVENTION

All literature references, patents and patent applications cited in thisspecification are hereby incorporated by reference in their entirety.

The present invention relates to a synthetic, crystallinealuminosilicate and a method for using the same as catalyst componentsin petrochemical processes for the conversion of hydrocarbons and theirderivatives into valuable organic compounds.

The chemical composition of the synthetic crystalline aluminosilicatesof the invention is described in terms of molar ratios in the followingmanner:

    (0-3) M.sub.2 O:Al.sub.2 O.sub.3 :(15-40) SiO.sub.2 :(0-40) H.sub.2 O

wherein M represents an alkali metal cation such as sodium, potassium,or lithium, preferably sodium; a proton or an ammonium compound.

The synthetic crystalline aluminosilicates are produced by hydrothermalcrystallization from an inorganic aqueous alkaline reaction mixturecontaining silicon dioxide and aluminum oxide or their hydratedderivatives or alkali silicates and aluminates and mineral acid.Preferably, relatively inexpensive starting materials of sodium waterglass (sodium silicate) and sulfuric acid as mineral acid are used.

The reaction mixture contains SiO₂ /Al₂ O₃ at a molar ratio of betweenabout 15 and about 40, preferably between about 20 to about 30; OH⁻/SiO₂ at a molar ratio between about 0.1 to about 0.2, preferablybetween about 0.13 to about 0.16; and H₂ O/SiO₂ at a molar ratio betweenabout 20 and about 60, preferably between about 30 to about 40.

The reaction mixture, contained in a stirred autoclave, is subjected tohydrothermal crystallization conditions. In general, the reaction isconducted at a constant temperature between about 100° C. to 325° C.,preferably between about 180° C. to about 250° C. for a time period ofabout 1 to about 100 hours, preferably about 24 hours during which thecrystalline product precipitates out.

The aluminosilicates of the present invention can be crystallized in asingle step at a constant temperature and within a predetermined timeperiod or in a series of steps. For example, the mixture can bemaintained at different constant temperatures for various time periods,or at a plurality of different temperatures for a different time periodat each temperature but only within the aforementioned time andtemperature ranges.

Optionally, partially or totally crystalline aluminosilicate seedmaterial can be added to the reaction mixture to increase thecrystallization rate. The amount of seeding material that can be addedis generally about 1 to about 10%, preferably about 1 to about 3% byweight of the total mixture.

The crystalline aluminosilicate is then separated from the mixture byconventional means, e.g. filtration, and throughly washed with water toremove adhering impurities. The aluminosilicate is then dried at about150° C. for about 7 hours. The general yield of aluminosilicate crystalsrecovered is about 80 to about 99%, usually 95%.

In general, the crystalline aluminosilicates have a particle sizebetween about 0.1 to about 10 μm, usually about 3 μm. The pore size ofthe inventive aluminosilicates, as determined by XRD structure analysis,generally range between about 5.4 and about 5.7 angstroms, usually about5.5 angstroms. The surface area of the aluminosilicate of the presentinvention is generally greater than 300 m² /gm as determined by theconventional BET method.

Thereafter, the inventive aluminosilicate is then subjected to an ionexchange process with an ammonium compound or a mineral acid toultimately produce effective, heterogeneous acidic catalysts. Methodsfor carrying out ion exchange reactions of zeolites are well known inthe art and are described, for example, in Jacobs, P. A. et al. (1987)Stud. Surf. Sci. Cat. Vol. 33.

Non-limiting examples of suitable mineral acids for use in the exchangeprocess include sulfuric acid, hydrochloric acid, and nitric acid.Preferred mineral acids are sulfuric acid and hydrochloric acid.

Suitable, but non-limiting examples, of ammonium compounds includeammonium sulphate, ammonium nitrate, ammonium chloride, and ammoniumacetate. Preferred ammonium compounds for use in the present inventionare ammonium sulphate and ammonium chloride. The concentration ofammonium compound in solution is broadly between about 0.1 and about 5N,preferably about 1N.

The aluminosilicate treated by an ion exchange process is then convertedby a subsequent calcination into an active hydrogen form at atemperature above 300° C., preferably between about 400° and about 600°C.

The active hydrogen form of the aluminosilicate can be transformed intofinished catalysts by the addition of inorganic or organic binders andoptionally metal or metal oxide components.

Non-limiting examples of inorganic binders suitable for use with theinventive aluminosilicate are amorphous silica, pseudo-boehmite, kaolin,and other clays or a combination of the foregoing. Optional organicbinders or auxiliaries, such as polyvinyl alcohol, may be added.Preferred binders for use in this invention are amorphous silica andkaolin. The aluminosilicates can also be mixed with a variety ofcommercial catalysts, e.g. octane enhancing fluid catalystic cracking(FCC) additives.

Suitable examples of metal components which can be used with theinventive aluminosilicate include elements of the 4th and 6th period ofthe periodic table. Preferred metals are Zn, Mo, W, Pd, Ga, Pt orcombinations thereof.

Non-limiting examples of metal oxide components include gallium oxide,molybdenum oxide, nickel-oxide, platinum oxide, and palladium oxide.Preferred metal oxides for use are gallium-oxide, molybdenum oxide andnickel-oxide.

The inventive aluminosilicates have a largely homogeneous distributionof aluminum over the cross section of the crystals as shown in FIGS. 4and 5. By comparison, FIG. 6 shows the accumulation of aluminum at thecrystalline edge of an aluminosilicate prepared by a conventional methodin the art.

The elementary distributions of silicon and aluminum over thecross-section of the aluminosilicate of the A, B and C-type (FIGS. 4 to6) were determined by means of an electron beam micro-probe IEOL 1XA-733with a DEC-computer PDP 11/23. Samples were embedded into resin,polished with diamond paste and sputtered with gold. The electron beammeasurements were conducted with a voltage of 15 kV and a correctintensity of 50 μA. The elementary distributions of aluminosilicatetypes A, B, C were obtained by electron beam deflection and theresultant scanning electron micrographs of the crystals were recorded onphotopaper.

The aluminosilicates of the invention have a surface molar ratio of SiO₂:Al₂ O₃ which is equal to or greater than the interior molar ratio ofSiO₂ :Al₂ O₃. The ratio of surface molar ratio of SiO₂ :Al₂ O₃ to theinterior molar ratio of SiO₂ :Al₂ O₃ in the aluminosilicates of theinvention is broadly between about 1:1 and about 1.5:1, preferablybetween about 1:1 and about 1.1:1.

The inventive aluminosilicates can be physically distinguished fromconventional aluminosilicates by means of X-ray crystal diffractionpatterns and by solid state NMR spectroscopy. For example, the X-raydiffraction diagrams of the inventive aluminosilicate contain at leastthe distances between the crystalline lattice shown in Table 1.

The aluminosilicates prepared by the method of the present inventionproduce a ²⁹ Si solid state Magic Angle Spin (MAS) NMR spectrum withcharacteristic absorption bands at -100, -106, -112, and -116 ppmrelative to the adsorption band of tetramethylsilane. Thehigh-resolution solid-state NMR spectra shown in FIGS. 1 to 3 wereperformed with a Bruker 400 MSL spectrometer with a magnetic field of9.4 T. The ²⁹ Si high-resolution NMR measurements were conducted at afrequency of 79.5 MHz with a pulse length of 4 microseconds, a pulseinterval of 5 seconds, an spin rpm of 3 KHz with a total of 10,000 scanaquisitions. The Bruker GLINFIT program was used for simulating theindividual peaks in the measured spectrum.

The inventive aluminosilicate can be used as a catalyst or a componentof heterogenous catalysts in petrochemical processes for the catalyticconversion of hydrocarbons or their derivatives.

In processes where the aluminosilicate is employed, the operationalpressures are generally between about 0.1 and about 15 MPa, preferablybetween about 1 and about 10 MPa; the temperatures are generally betweenabout 250° and about 600° C., preferably between about 300° and about500° C.; and with raw material loads between about 0.5 and about 10(v/v/hour), preferably between about 2 and about 8 (v/v/hour). Suchprocesses can be conducted in the presence of hydrogen gas orhydrogen-containing gases in molded catalysts containing the inventivealuminosilicate.

In one embodiment of the invention, the aluminosilicates can be employedin processes for dewaxing or removing paraffins from hydrocarbonfractions. Long-chain linear or slightly branched paraffins have highermelting points than do other hydrocarbons with the same number of carbonatoms. Small amounts of such wax-like components in mixtures, e.g. fueldistillates and lubricating oils, can negatively affect the flowbehavior (pour point, freezing point, cloud point).

Unlike narrow pore zeolites, e.g. erionite, having shape-selectivecracking properties restricted to gasolines, the medium porealuminosilicates are especially suitable for selectively crackingparaffins and removing them from mixtures such as jet fuel anddistillation residues. Example 5 illustrates the utility of theinventive aluminosilicates in dewaxing hydrocarbon fractions.

In another embodiment of the invention, the aluminosilicates of thepresent invention are used in processes for the isomerization of xylene.In general, the starting materials for xylene isomerization are mixturesof C₈ aromatic compounds consisting of ethyl benzene as well as ortho-,meta- and paraxylene. Para- and ortho-xylenes are importantintermediates for the production of plastics.

In xylene isomerization processes, two goals must be met (1) to achievean equilibrating isomer population of 50% m-xylene and 25% each ofortho- and para-xylene after a large portion of para-xylene has beenremoved and (2) to convert ethylbenzene into xylenes. For optimizationof the isomerization process, it is important that the zeolite catalyzesisomer equilibration under conditions which maximal ethylbenzeneconversion occurs. Example 6 illustrates the utility of the inventivealuminosilicate in xylene isomerization.

In yet another embodiment of the invention, the inventivealuminosilicate is used in processes for the alkylation of aromaticcompounds with low molecular weight alkenes and alcohols.Aluminosilicates have proven useful in processes for preparing xylenefrom toluene; methanol and ethylbenzene from benzene and ethene;para-ethyltoluene from toluene and ethyl ether or ethanol;diethylbenzene from ethylbenzene and ethene; dimethylbenzene from xyleneand ethene; cumene from benzene and propene; alkylbenzene from benzeneand low molecular weight alcohols; and diethylbenzene from ethylbenzeneand ethanol. Example 7 illustrates the utility of the inventivealuminosilicates in the alkylation of benzene and ethylbenzene withethene. In addition, Example 8 illustrates the use of the inventivealuminosilicates in the alkylation of toluene with methanol.

In another embodiment of the invention, the aluminosilicates are used incatalytic, fluidized bed cracking processes for the conversion of vacuumdistillates and distillation residues into high-grade fuels with highresearch octane numbers/motor octane numbers. For this purpose,catalysts, such as FCC catalysts, which incorporate aluminosilicatezeolites in its matrix are generally employed. Examples of FCC catalystsinclude Y-zeolites and rare earth exchanged y-zeolites. The addition ofpentasil zeolites in the finished catalyst brings about the eliminationof low-octane paraffin fractions and the formation of C₃ and C₄ olefinswhich are useful starting material for alkylation reactions. Example 9illustrates the use of the inventive aluminosilicates in a process forcracking high-boiling hydrocarbon fractions. In addition, Example 10details the use of the inventive aluminosilicates in a process forisomerizing low molecular weight n-paraffins to improve the front octanenumber.

In a further embodiment of the invention, the aluminosilicates are usedin processes for obtaining aromatic compounds from low molecular weighthydrocarbons. Traditionally, aromatics from crude oil are produced by agas reforming process. This process, however, is able to aromatize onlyhydrocarbons having at least six carbon atoms. In recent years,utilization of light hydrocarbon fractions (C₂ to C₅) particularly inliquified form has become more important for obtaining high-grade liquidproducts. Conventional aromatizing catalysts which catalyze thedehydrocyclodimerization of light fractions also form coke whichdeactivates the catalyst during prolonged operations. Accordingly,shape-selective zeolites with low coking tendencies would beparticularly suitable in such processes. Example 11 describes the use ofthe inventive aluminosilicates in a process for generating aromaticcompounds from low molecular weight hydrocarbons.

In a still further embodiment of the invention, the synthetic aluminatesare used in processes for obtaining liquid hydrocarbons or low molecularweight alkenes from methanol. Methanol derived from known processes fromnatural gas or coal is an important intermediate for the production ofhigh-grade hydrocarbons. Pentasil zeolites have shown utility incatalytic processes for the conversion of methanol into higher molecularweight hydrocarbons such as high-grade gasoline for carburetor-typegasoline engines, aromatic compounds as intermediates for the plasticsindustry and alkenes. Example 12 describes in detail the utility of theinventive aluminosilicates in a process for obtaining liquidhydrocarbons or low molecular weight alkenes from methanol.

The following examples illustrate the invention without limiting itsscope.

Example 1 Synthesis of an Aluminosilicate of Type A

A 25,000 liter reaction solution containing sodium water glass, aluminumsulfate, sodium sulfate and sulfuric acid in the molar ratios of: SiO₂/Al₂ O₃ =30; OH⁻ /SiO₂ =0.14; H₂ O/SiO₂ =30 is heated in a stirred35,000 liter autoclave to a reaction temperature of 185° C. and pressureof 10 bar for 24 hours. The solid product (>90% yield) is filtered offand dried at 110° C. The dry substances consist of a pure-phasealumino-silicate with an X-ray diffraction diagram with at least the dvalues (angstroms) that are listed in Table 1 below. The peak-planeintensities are relative to the strongest peak which is set at 100%.

                  TABLE 1                                                         ______________________________________                                        d Value/Interlattice Plane                                                    Distance (in angstroms)                                                                            Relative Intensity                                       ______________________________________                                        11.2 ± 0.3        strong                                                   10.2 ± 0.3        strong                                                   9.8 ± 0.2         weak                                                     3.85 ± 0.1        very strong                                              3.83 ± 0.1        strong                                                   3.75 ± 0.1        strong                                                   3.73 ± 0.1        strong                                                   3.60 ± 0.1        weak                                                     3.60 ± 0.05       weak                                                     3.00 ± 0.05       weak                                                     2.01 ± 0.02       weak                                                     1.99 ± 0.02       weak                                                     ______________________________________                                    

The chemical composition of the product, expressed in molar ratios, is:1.1Na₂ O:Al₂ O₃ :31SiO₂ :6H₂ O. FIG. 4 shows the aluminum distributionover the cross section of the crystals of the products.

The proportions of the individual absorption bands, which were obtainedfrom the ²⁹ Si solid state MAS nuclear magnetic spectra (FIG. 1) and area measure of the different tetrahedral coordination of silicon, occurat:

    ______________________________________                                        Si(4SiOA1) %     Si(3Si1Al)                                                                              Si(2Si2Al)                                         -112 and -116 ppm                                                                              -106 ppm  -100 ppm                                           ______________________________________                                        75               23        2                                                  ______________________________________                                    

EXAMPLE 2 Synthesis of an Aluminosilicate of Type B

In accordance with Example 1, a reaction formulation of a solution ofsodium water glass, aluminum sulfate, sodium sulfate and sulfuric acidin the molar ratios of: SiO₂ /Al₂ O₃ =24; OH⁻ /SiO₂ =0.14; H₂ O/SiO₂ =30is heated in stirred autoclave to a reaction temperature of 185° C. andtreated hydrothermally for 24 hours. The solid product is filtered offand dried at 110° C. The dry substance consists of a pure-phasealuminosilicate with an X-ray diffraction diagram with at least the dvalues that are listed in Table 1 shown in Example 1.

The chemical composition of the product, expressed in molar ratios, is:1.1Na₂ O:Al₂ O₃ :23SiO₂ :7H₂ O. FIG. 5 shows the aluminum distributionover the cross section of the crystals of the products.

The proportions of the individual absorption bands, which were obtainedfrom the ²⁹ Si solid state MAS nuclear magnetic spectrum (FIG. 2) andare a measure of the different tetrahedral coordination of silicon,occur at:

    ______________________________________                                        Si(4SiOA1) %     Si(3Si1Al)                                                                              Si(2Si2Al)                                         -112 and -116 ppm                                                                              -106 ppm  -100 ppm                                           ______________________________________                                        71               26        3                                                  ______________________________________                                    

EXAMPLE 3 Preparation of a Conventional Comparison Aluminum Silicate ofType C

A reaction formulation of pyrogenic silica, tetrapropylammonium bromide,glycerol, ammonia, sodium hydroxide, aluminum nitrate and with the molarratios of: SiO₂ /Al₂ O₃ =72; Na₂ O/SiO₂ =0.2; TPA/SiO₂ =1.25;glycerol/SiO₂ =19.86; NH₃ /SiO₂ =0.2; H₂ O/SiO₂ =146 is heated in astationary autoclave to a reaction temperature of 150° C. and treatedhydrothermally for 72 hours. The reaction components and conditions aredescribed in (1987) Jacobs, P. A. et al. Stud. Surf. Sci. Catal. Vol.33. The solid product is filtered off and dried at 110° C. The producthas a SiO₂ /Al₂ O₃ ratio of 70.

The aluminum distribution of the cross section of crystals of theconventional comparison silicate is shown in FIG. 6. Moreover, thisproduct does not show any absorption bands in the 29-silicon solid MASnuclear resonance spectrum at -100 ppm (see FIG. 3).

EXAMPLE 4 The Preparation of Catalysts from crystalline Aluminosilicate

Catalyst 1

A synthetic, crystalline aluminosilicate of type B prepared inaccordance with Example 2 is repeatedly subjected to an ion exchangeprocess with aqueous 1N ammonium sulphate solution and subsequentlymixed in a kneader in an amount of 70% aluminosilicate to 30% inorganicbinder of aluminum oxide as psuedo-boehmite by weight of the mixture,with the addition of 3% by weight of concentrated nitric acid. Thecatalyst is then molded to extrudates of 3 mm diameter and activated ata temperature of 400° C.

Comparison Catalyst 2

A zeolite of type C, synthesized by the method of Jacobs, P. A. et al.(Example 10a on page 19 in "Synthesis of High-Silica Alumino-silicateZeolites" in Stud. Surf. Sci. Catal., 33 (1987)) withtetrapropylammoniumbromide as structure-directing compound in accordancewith Example 3. The zeolite is repeatedly subjected to an ion exchangeprocess with an aqueous 1N ammonium sulphate solution and subsequentlymixed in a kneader in an amount of 70% aluminosilicate to 30% inorganicbinder of aluminum oxide as pseudo-boehmite by weight of the mixture,with addition of 3% by weight of concentrated HNO₃. The catalyst is thenmolded to extrudates of 3 mm diameter and activated at a temperature of400° C.

Catalyst 3

A synthetic, crystalline aluminosilicate of type A, prepared inaccordance to Example 1, is repeatedly subjected to an ion exchangeprocess with aqueous ammonium sulphate solution and subsequently mixedin a kneader in an amount of 70% aluminosilicate to 30% inorganic binder(see catalyst 1) by weight of the mixture and molded to extrudates of 3mm diameter. Subsequently, the molded catalyst is coated with 3% byweight of molybdenum oxide by impregnation with 1N ammonia molybdate andactivated at a temperature of 400° C.

Comparison Catalyst 4

A zeolite of type C, synthesized by the method of Jacobs, P. A. et al.(Example 10a on page 19 in "Synthesis of High-Silica Alumino-silicateZeolites" in Stud. Surf. Sci. Catal., 33 (1987)) withtetrapropylammonium bromide as structure-directing compound inaccordance with Example 3. This zeolite is repeatedly subjected to anion exchange process with an aqueous ammonium sulphate solution andsubsequently mixed in a kneader in an amount of 70% aluminosilicate to30% inorganic binder (see catalyst 1) by weight of the mixture andmolded into extrudates with a diameter of 3 mm. The molded catalyst issubsequently coated with 3% by weight of molybdenum oxide byimpregnation with 1N ammonia molybdate solution and activated attemperatures of 400° C.

Catalyst 5

A synthetic, crystalline aluminosilicate of type B prepared inaccordance to Example 2 is repeatedly subjected to an ion exchangeprocess with aqueous 1N ammonia sulphate solution and subsequently mixedin a kneader in an amount of 70% aluminosilicate to 30% inorganic binder(see catalyst 1) by weight of the mixture and molded to extrudates of 3mm diameter. Subsequently, the molded catalyst is coated with 2% byweight of gallium oxide by impregnation with a gallium chloride solutionin hydrochloric and activated at a temperature of 400° C.

Catalyst 6

A zeolite of type C is synthesized by the method of Jacobs, P. A. et al.(Example 10a on page 19 in "Synthesis of High-Silica Alumino-silicateZeolites" in Stud. Surf. Sci. Catal., 33 (1987)) withtetrapropylammonium bromide as structure-directing compound as describedin Example 3. This zeolite is repeatedly subjected to an ion exchangeprocess with a 1N ammonium sulphate solution and subsequently mixed in akneader in an amount of 70% aluminosilicate to 30% inorganic binder (seecatalyst 1) by weight of the mixture, and molded to extrudates of 3 mmdiameter. The catalyst is subsequently coated with 2% by weight ofgallium oxide by impregnation with a gallium chloride solution inhydrochloric acid and activated at temperatures of 400° C.

Catalyst 7

A synthetic, crystalline aluminosilicate of type A prepared inaccordance with Example 1 is repeatedly subjected to an ion exchangeprocess with aqueous 1N ammonium sulphate solution and subsequentlymixed in a kneader in an amount of 70% aluminosilicate to 30% inorganicbinder (see catalyst 1) by weight of the mixture and molded toextrudates of 3 mm diameter. Subsequently, the molded catalyst is coatedwith 2% by weight of zinc nitrate by impregnation with a 1N zinc nitrateaqueous solution and activated in a current of hydrogen at a 40 bar H₂pressure and a temperature of 400° C.

Comparison Catalyst 8

A zeolite of type C is synthesized by the method of Jacobs, P. A. et al.(Example 10a on page 19 in "Synthesis of High-Silica Alumino-silicateZeolites" in Stud. Surf. Sci. Catal., 33 (1987)) withtetrapropylammonium bromide as structure-directing compound as describedin Example 3. This zeolite is repeatedly subjected to an ion exchangeprocess with a 1N aqueous ammonium sulphate solution and subsequentlymixed in a kneader in an amount of 70% aluminosilicate to 30% inorganicbinder (see catalyst 1) by weight of the mixture, and molded toextrudates of 3 mm diameter. The catalyst is subsequently impregnatedwith a zinc nitrate (2% by weight) with 1N zinc nitrate aqueous solutionand activated in a current of hydrogen at a 40 bar H₂ pressure and atemperature of 400° C.

EXAMPLE 5 Comparison of aluminosilicate catalysts in dewaxinghydrocarbon fractions

A gas oil (a crude oil distillate with a boiling point between about290° C. and about 350° C.) with a density of 0.865 kg/L, a nitrogencontent of 142 mg NH₃ /L and a BPA point (temperature at which paraffincommences to precipitate) of 3° C. is reacted at a pressure of 3.5 MPa,a loading of 2 (v/v/hour) and a gas product ratio (GPV) of 1000:1 at aninitial temperature of 663° K. on catalyst 7 and, in a separate run, onthe conventional, comparison catalyst 8. The units (v/v/hour) refers tothe volume of "liquid" educt, e.g. gas oil, divided by the volume ofcatalyst per hour. The results of the catalytic dewaxing are listed inthe Table below:

The inventive catalyst 7 has a low fouling rate (T/day) and thus ahigher stability with about the same initial activity as catalyst 8.

    ______________________________________                                                     Starting                                                         Parameters   Material  Catalyst 7 Catalyst 8                                  ______________________________________                                        Density (kg/L)                                                                             0.865     0.859      0.858                                       BPA (°C.)                                                                           3° C.                                                                            -15/-25    -15/-25                                     T/day (°K.)     0.17       0.48                                        ______________________________________                                    

T/day was determined over a period of 30 days and refers to thetemperature (°K.) per day which has to be increased in order for thereaction to receive the same BPA point.

EXAMPLE 6 Comparison of Aluminosilicate catalysts in the isomerizationof Xylene

A C-8 mixture of aromatic compounds is converted at a pressure of 1.0MPa, a temperature of 400° C., a load of 2.0 (v/v/hour) and a gasproduct ratio (GPV) of 1000:1 on catalyst 3 and, in a separate run, onthe conventional catalyst 4. The results of the conversion of the C-8aromatic compounds are listed in the Table below.

    ______________________________________                                        Compounds Raw Material Catalyst 3                                                                              Catalyst 4                                   ______________________________________                                        Non-aromatics                                                                           1.09         0.45      0.71                                         Benzene                14.39     5.32                                         Toluene   0.71         6.62      5.04                                         Ethylbenzene                                                                            23.75        2.79      12.24                                        para-xylene                                                                             9.73         17.89     16.01                                        meta-xylene                                                                             47.57        40.38     38.12                                        ortho-xylene                                                                            16.44        16.29     15.27                                        C.sub.9 .sup.+  aromatics                                                               0.71         1.35      7.29                                         Total xylenes                                                                           73.74        74.5      69.4                                         ______________________________________                                    

Compared to the comparison catalyst 4, the inventive catalyst 3 exhibitsa far higher ethylbenzene conversion and, at the same time, a betterxylene selectivity (fewer aromatic materials).

EXAMPLE 7 Comparison of aluminosilicate catalysts in a process foralkylation of aromatic compounds

A mixture of benzene and ethene, in a ratio of 1:2.6 gm/gm, is convertedat 400° to 420° C. at a load of 6.5/hour (benzene plus ethene) overcatalyst 1 and, in a separate run, over the conventional comparisoncatalyst 2.

Compared to the comparison catalyst 2, the inventive catalyst 1, has aslightly higher activity and selectivity for ethylbenzene anddiethylbenzene and a distinctly better selectivity forpara-diethylbenzene.

    ______________________________________                                                         Catalyst 1  Catalyst 2                                       Results          % Conversion                                                                              % Conversion                                     ______________________________________                                        Conversion of benzene                                                                          28          26                                               Conversion of ethene                                                                           81          72                                               Selectivity of the benzene to                                                                  95          92                                               ethylbenzene + diethylbenzene                                                 Selectivity of the ethene to                                                                   90          90                                               ethylbenzene + diethylbenzene                                                 Proportion of para-diethyl-                                                                    85          60                                               benzene in diethylbenezene                                                    ______________________________________                                    

EXAMPLE 8 Comparison of Aluminosilicate catalysts in a process foralkylation of toluene with methanol

A mixture of toluene and methanol in the ratio of 2:1 is converted at atemperature of 350° C. and a loading of 4/hour (toluene plus methanol)over catalyst 1 and, in a different run, over the conventionalcomparison catalyst 2. The results of the alkylation reaction are listedin the Table below.

The inventive catalyst 1 shows a distinctly higher activity and aslightly better para selectivity than does the comparison catalyst 2.

    ______________________________________                                                         Catalyst 1  Catalyst 2                                       Results          % Conversion                                                                              % Conversion                                     ______________________________________                                        Methanol conversion                                                                            100         80                                               Toluene conversion                                                                             30          17                                               Benzene          1           0.5                                              Toluene          51          61                                               meta-Xylene      8           4                                                para-Xylene      11          3.9                                              ortho-Xylene     7           3.0                                              Total C8 aromatic compounds                                                                    26          11                                               ______________________________________                                    

EXAMPLE 9 Comparison of Aluminosilicate catalysts in a process forcracking higher-boiling hydrocarbon fractions

Catalyst 1 and catalyst 2 are each metered in as additive (5% by weight)to a conventional commercial fluidized bed catalyst or moving bedcatalyst that is based on a Y zeolite. After a steam treatment of thecatalysts at 750° C. for 17 hours, a hydrated gas oil is passed at atemperature of 475° C. and a load of 10/hour over the mixed catalyst.The results of the cracking experiments are listed in the Table below.

Compared to the comparison catalyst, the inventive catalyst brings abouta slightly higher gas yield, a somewhat better gasoline yield and adistinctly lower proportion of coke. The isooctane portion increasesgreatly, so that the octane number is clearly improved. Likewise, theproportions of C₃ and C₄ olefins is increased; this is associated withan improvement in the research octane number.

    ______________________________________                                                  Conventional With 5%   With 5%                                                Catalyst     Catalyst 1                                                                              Catalyst 2                                   Results   (% yield)    (% yield) (% yield)                                    ______________________________________                                        Methane   0.5          0.5       0.5                                          Ethane    0.7          0.7       0.7                                          Ethene    0.6          0.5       0.5                                          Propane   3.3          4.7       3.5                                          n-Butane  2.7          2.9       2.8                                          i-Butane  2.0          1.9       1.9                                          Total C.sub.4                                                                           6.7          7.9       6.8                                          C.sub.5 - C.sub.2                                                                       1.5          1.8       1.7                                          (Gasoline)                                                                              50.2         48.5      48.2                                         Coke      8.4          5.8       8.1                                          ______________________________________                                    

EXAMPLE 10 Comparison of aluminosilicate catalysts in a process for theisomerization of low molecular weight n-paraffins

A 1:10 n-hexane/hydrogen mixture (gm/gm) is reacted at 300° C. and 4 MPaand a load of 1/hour on catalyst 7 and, in a separate run, on aconventional comparison catalyst 8 for comparison. The results of thereaction are listed in the Table below:

    ______________________________________                                                          Catalyst 7                                                                              Catalyst 8                                        Results           (% yield) (% yield)                                         ______________________________________                                        n-Hexane conversion                                                                             48        25                                                Hexane isomers/cracked prod.                                                                    1.3       1.2                                               ______________________________________                                    

Compared to the conventional comparison catalyst, the inventive catalyst7 shows a clearly higher activity and a slightly better hexaneisomer/cracked products ratio.

EXAMPLE 11 Comparison of aluminosilicates in a process for preparingaromatic compounds from low molecular weight hydrocarbons

n-Pentane is converted at a pressure of 0.1 MPa and a load of 1/hour ata temperature of 500° C. on catalyst 5 and, in a different run, on theconventional comparison catalyst 6. The results of the aromatizationreaction are listed in the Table below.

    ______________________________________                                                         Catalyst 1                                                                              Catalyst 2                                         Results          (% yield) (% yield)                                          ______________________________________                                        Liquid product   45        39.2                                               Gases            54.1      60.3                                               Carbon           0.9       0.5                                                Aromatic products                                                                              44.5      38.5                                               ______________________________________                                    

Compared to the conventional catalyst 6, the inventive catalyst 5 showsa better yield of aromatic compounds.

EXAMPLE 12 Comparison of aluminosilicate catalysts in a process forpreparing liquid hydrocarbons and low molecular weight alkenes frommethanol

Methanol is converted at a pressure of 0.1 MPa, a temperature of 300° C.and a load of 1/hour on catalyst 1 and, in a different run, on theconventional comparison catalyst 2. The results of the reaction arelisted in the Table below.

    ______________________________________                                        Results          Catalyst 1                                                                              Catalyst 2                                         ______________________________________                                        Conversion       99%       77%                                                Olefins          33%       23%                                                Aromatic materials                                                                             12%       15%                                                ______________________________________                                    

Compared to conventional comparison catalysts, the inventive catalyst 1shows a clearly higher activity and an improved olefin yield.

What is claimed is:
 1. A process for the conversion of hydrocarbons intovaluable intermediates comprising contacting said hydrocarbons with acatalyst comprising a synthetic crystalline aluminosilicate having thefollowing chemical composition in terms of molar ratio:(0-3)M₂ O:Al₂O_(3:) (15-40) SiO_(2:) (0-40) H₂ O wherein M represents a metal cation,a proton, or an ammonium compound, said aluminosilicate having(I) a SiO₂/Al₂ O₃ molar ratio at the surface of the crystalline structure that isequal to or greater than the SiO₂ /Al₂ O₃ molar ratio in the interior ofthe crystalline structure, (ii) said crystalline aluminosilicate has anX-ray diffraction diagram with X-ray reflections belonging to thefollowing d values:

    ______________________________________                                        d Values/Interplanar                                                          Spacing             Relative Intensity                                        ______________________________________                                        11.2 ± 0.3       strong                                                    10.2 ± 0.3       strong                                                     9.8 ± 0.2       weak                                                      3.85 ± 0.1       very strong                                               3.83 ± 0.1       strong                                                    3.75 ± 0.1       strong                                                    3.73 ± 0.1       strong                                                    3.60 ± 0.1       weak                                                       3.06 ± 0.05     weak                                                       3.00 ± 0.05     weak                                                       2.01 ± 0.02     weak                                                       1.99 ± 0.02     weak.                                                     ______________________________________                                    


2. The process according to claim 1, wherein said aluminosilicate has a²⁹ Si solid MAS nuclear magnetic resonance spectrum with absorptionbands at about -100, -106, -112 and -116 ppm relative to the absorptionband of a tetramethylsilane standard.
 3. The process according to claim1, wherein said conversion comprises removing n-paraffins or branchedparaffins from hydrocarbon fractions by transforming said paraffins toform lower molecular weight hydrocarbons, at a pressure between about1.0 and about 1.5 MPa and a temperature between about 250° C. and about450° C.
 4. The process according to claim 1, wherein said conversioncomprises converting C₈ aromatic mixtures into ortho-xylene andparaxylene, at a pressure between about 0.5 and about 5.0 MPa and at atemperature between about 250° C. and about 500° C; wherein said C₈aromatic mixture comprises ethyl benzene.
 5. The process according toclaim 1, wherein said conversion comprises alkylating aromatic compoundswith low molecular weight alkenes to form an alkylated product, at apressure between about 1.0 and about 5.0 MPa and at a temperaturebetween about 350° C. and about 500° C.
 6. The process according toclaim 5, wherein said aromatic compound comprises benzene, said lowmolecular weight compound comprises ethene and said alkylated productcomprises ethylbenzene.
 7. The process according to claim 5 wherein saidaromatic compound comprises benzene, said low molecular weight compoundcomprises propene and said alkylated product comprises cumene.
 8. Theprocess according to claim 1, wherein said conversion comprisesalkylating aromatic compounds with low molecular weight alcohols, at apressure between about 0.1 and about 0.5 MPa and at a temperaturebetween about 250° C. and about 500° C.
 9. The process according toclaim 8, which comprises alkylating toluene with methanol to producexylenes.
 10. The process according to claim 1, wherein said conversioncomprises cracking higher boiling hydrocarbon fractions on a fluidizedor moving bed catalyst to form a lower boiling cracked product.
 11. Theprocess according to claim 1, wherein said conversion comprisesisomerizing lower molecular weight n-paraffins to isoparaffins, at apressure between about 0.5 and about 5 MPa and at a temperature betweenabout 200° C. and about 500° C.
 12. The process according to claim 1,wherein said conversion comprises preparing aromatic compounds from lowmolecular weight hydrocarbons, at a pressure between about 0.5 and about5.0 MPa and at a temperature between about 500° C. and about 600° C. 13.The process according to claim 1, wherein said conversion comprisesconverting methanol to liquid hydrocarbons, low molecular weightalkanes, or alkenes, at a pressure between about 0.5 and about 5.0 MPaand at a temperature between about 250° C. and about 550° C.
 14. Theprocess according to claim 1, wherein said conversion comprisesconverting a mixture of benzene and ethene to ethylbenzene, at atemperature between about 400° C. and about 420° C. at a load of about6.5 v/v/hr.
 15. The process according to claim 14, wherein said mixturecomprises benzene and ethene in a ratio of 1:2.6.
 16. The processaccording to claim 1, wherein said conversion comprises dewaxinghydrocarbons, at a temperature between about 390° C. and about 450° C.at a load of about 2.0 v/v/hr.
 17. The process according to claim 1,wherein said conversion comprises isomerizing xylene, at a temperaturebetween about 350° C. and about 450° C. at a load of about 2.0 v/v/hr.18. The process according to claim 1, wherein said conversion comprisesalkylating toluene with methanol, wherein the mixture of toluene andmethanol is at a ratio of about 2:1; at a temperature between about 300°C. and about 400° C., and at a load of about 4 v/v/hr.
 19. The processaccording to claim 1, wherein said conversion comprises crackinghydrated gas oil, at a temperature between about 450° C. and about 500°C. at a load of about 10 v/v/hr.
 20. The process according to claim 1,wherein said conversion comprises isomerizing low molecular weightn-paraffins, at a temperature between about 250° C. and about 350° C. ata load of about 1 v/v/hr.
 21. The process according to claim 1, whereinsaid conversion comprises preparing aromatic compounds from lowmolecular weight hydrocarbons, at a temperature between about 500° C.and about 600° C. at a load of about 1 v/v/hr.
 22. The process accordingto claim 1, wherein said conversion comprises preparing C₄ to C₁₂ liquidhydrocarbons and low molecular weight alkenes (<C₆) from methanol, at atemperature between about 250° C. and about 500° C. at a load of about 1v/v/hr.